Accumulating TAG in cells has been previously performed by introducing a TAG synthase gene into algae such as Chlamydomonas reinhardtii (hereinafter sometimes referred to as “C. reinhardtii”) (Patent Literature 1, non-Patent Literature 1).
For example, non-Patent Literature 1 describes a method comprising introducing DGAT2 gene linked to a strong expression promoter of psaD into C. reinhardtii, culturing this under nitrogen or sulfur starvation conditions, and accumulating the TAGs in cells. Patent Literature 1 also describes C. reinhardtii into which DGAT2 gene linked to psaD was introduced, as is the case with non-Patent Literature 1.
With regard to producing TAGs, algae belonging to Nannochloropsis as well as C. reinhardtii have been attracting attention. The algae can be cultured at about 100 times higher density than C. reinhardtii, so it is assumed that they are more suitable for producing TAGs than C. reinhardtii. 